LAEUS GLAUCESCEXS, GLAUCOUS-WINGED GULL. 623 

 <r 



N. A. Introd. fig. of primaries (with labels of thisaod the accompanyinjr figure 

 tiaosposed). — Dall & Ba.vx., Tr. Chic. Acad. ItOO, 304.— Fixsch, Abh. Nat. iii, 



Glancus glaucescens, Bi;uCH, J. f. 0. 1853, 101. 



Laruides glaucesceitu, Br.uCH, J. f. O. 1855, 281. 



Zeucus glaucescens, Bp., Consp. Av. ii, 1856, 216 ; Compt. Eend. xlii, 1?56, 770. 



Lama glaucopterus, " Kn'rLi rz." 



Glmicits glaucopterus, Beuch, J. f. O. 1853, 101. 



Zaroides chalcopterun, Bruch, J. f. O. 1^'jp, 2-<2. 



Zeucus clialcoplerus, Bp., Consp. Av. ii, 1856, 216 ; Compt. Rend, xlii, 1^56, 770. 



Zarus chalcoptet-us, Lawi;., B. N. A. 18.oci, 843.— CouES, Pr. Phila. Acad. 1862, 295. 



DiAO. L.paUio cwruUo-perlaceo fere ut in Z. argentato, pnmariis dorio concoloribus, apid- 

 iii8 statim nee sen»im alhis. 



(The shade of the mantle is almost exactly as in argentatiis, and the primaries are 

 pictnred exactly as in that species, the black of argenlatua being replaced by a pearly- 

 blae like the mantle.) 



Sp. Ch.— Bill long and rather weak, the upper mandible acnte and projecting con- 

 siderably beyond tip of the nnder, the convexity near the end comparatively slight ; 

 angle pretty well defined, the outline between it and the tip about straight. First 

 primary longest ; the tarsus rather longer than the middle toe and claw. 



Adult in summer. — Bill light yellow, an orange spot at the angle of the lower mandi- 

 ble, and a dusky one just above. Mandible pearl-blue, much the same shade as in 

 argeniatus. Primaries scarcely darker than the back, all with well-defined, rounded 

 apical spots of white. First, the base not appreciably lighter than the body of the 

 feather, with a well-defined white spot on both webs near the end, separated from the 

 white tip by a transverse band of the color of the body of the feather ; second, third, 

 and fourth, basal portions notably lighter than the terminal, fading into pure white at 

 their juncture with the latter, without spots except at the apex ; filth, sixth, basal por- 

 tions the color of the back, fading into white near the end, separated from the white 

 apices by a band, narrowest on the sixth, of the color of the outer primaries. Inner 

 primaries like the secondaries, with plain broadly white ends. Feet light flesh-color. 



Adult in lointer. — Head, neck, and breast thickly nebulated with light grayish-dnsky, 

 the throat mostly immaculate. 



Approaching maturity. — Bill dark-colored, yellowish along the cnlmen and gonys. 

 Wings and tail light grayish-ashy, the former without sbarply-defiued white tips or 

 spots. Under parts generally marked with dusky, the wing coverts marked with 

 dusky and white. Feathers of the back narrowly edged with gray. 



Zntermediate. — Bill flesh-colored, the terminal portion black. Win£;s and taU darker 

 than in the preceding, especially on the outer webs of the former. Everywhere du.sky- 

 gray, more or less mottled with white, the gull-blue of the upper parts appearing as 

 mottling of greater or le.s3 extent. 



Taung-of-the^ear. — Bill black. Everywhere deep grayish-dusky, somewhat mottled 

 with whitish; the feathers of the back, wings, and upper tail coverts edged, tipped, 

 and crossed with mere or less regular transverse bars of grayish-white. 



XestUng, nearly fledged. — Dark gray; under parts, wiD{,'.s, and tail transversely waved 

 with mfons ; under parts nearly pure dark ashy-gray : bill and feet black. 



Nestling, unfledged. — Bill and feet black ; head and neck dull whitish, irregularly 

 spotted wit h blackish ; upper parts spotted with grayish-black and gray ish -white ; 

 under parts more uniform gray, the abdomen fading into white. 



Dimensions. — Length, about 27 inches; wing, 16.75; bill above, 2.25; gape, 3.25; 

 height at angle, 0.70; tarsus, 2.60 ; middle toe and claw, 2..50. 



ITaJ). — Pacific coast of North America. 



The present is a well characterized species. The most striking peculiarity of form 

 is ia the bill, in the very slight comparative convexity of the culmen near the end, the 

 tip being slender and acute and projecting considerably over the tip of the lower man- 

 dible. This form of bill is recognizable even in the yonng-of-the-year, in which the 

 bill is every way much smaller than in the adult. The color of the upper parts is 

 much that of Z. argentatus. The terminal spots of the primaries are as well defined as 

 in the species with black primaries, and are much and regularly rounded. The shafts of 

 the quill-feathers are much the color of the webs. The dusky of the young birds is very 

 light, and, except in the early stages, is much mottled with grayish-white. The upper 

 parts soon become very light-colored by the broad whitish margins of the feathers. 

 The primaries early acquire notably lighter tips, but do not obtain the well-defined 

 white terminal apexes, nor the spot on the first primaries, till maturity. The prima- 

 ries of the youngest birds have a shade of silvery-gray, which is quite peculiar, and very 

 different from the color of those parts in the young of the Gulls with black primaries. 



Zarus glaucescens may be considered a well-established species. As already noted, 

 it is when adult almost exactly like an argentatus with the black of the primaries re- 



